The present invention relates to alternating current circuits and particularly to amplifier circuits for use in alternating current meters. Alternating current amplifier circuits amplify an alternating signal for driving a meter used in measuring the amplitude of an alternating signal. These circuits usually comprise a number of transistor stages in addition to a high input impedance field-effect transistor (FET) for amplifying the alternating signal, detecting the amplified signal and then applying the detected direct current voltage to a D.C. meter calibrated to indicate the magnitude of the alternating current voltage represented by the magnitude of the meter direct current.
However meter amplifiers heretofore utilized including field-effect transistors and bipolar transistors have not been completely satisfactory with respect to operating stability in the presence of temperature and bias voltage fluctuations. In view of these fluctuations it is desirable that the amplified waveform follow the signal to be measured with significant precision. Additionally, it is desirable to provide such an amplifier with high gain. However, as well known, gain is reduced to obtain stability in a given circuit. To overcome this conflict, prior art circuits utilize a number of stages which increase the circuit complexity and cost. Additionally, it is desirable to provide a circuit that is linear and is competitive with respect to production costs. This latter requirement entails that a circuit be simple and have as few components as possible.